Pressure-drop alarm for tires.



P. FREEMAN,

PRESSURE DROP ALARM FOR TIRES.

APPLICATION FILED MAY 5. I914.

. 1 1 44,834. Patented J me 29 1915 A TTUR/I/EVS UNITED STATES OFEICE rnnnrmriss FREEMAN, or men-mm), wasnmemom rnnsslmnqnnor ALARM FOB Trans.-

To all whom it may concern 7 Be it known that I, FRED P.;FREEMAN, a citizen of the United States, and a resident of Richland, in the county of Benton and State of Washington, have invented a new and Improved Pressure-Drop Alarm for Tires, of which the following is a full, clear, andcex act description. 1 This invention relates to an indicating or alarm system for use in connection with vehicles having pneumatic tires whereby the pressure drop in any tire will be immediately indicated, as well as the location of the particular tire.

The invention has for its general objects to provide an automatic alarm or indicating means of the character referred to which is comparatively inex 'ensive to manufacture.

and install, thoroug ly reliable and efiicient in'use and so designed as to be easily and conveniently controlled and manipulated.

A further object of the invention is the provision of an electric annunciator or drop for each tire which is connected with a source of current, and associated with each tire is apressure responsive device which is released when the pressure .drops to a certain point, whereby a switch is closed so that current will energize that annunciator provided for the particular tire in which the pressure has dropped, there being a bell or other alarm also included in circuit so as to warn the driver of the fact of the drop in pressure, and by means of the annunciators he can ascertain at a glance which is the tire that needsrepairing or inflating.

A further object of the invention is the provision of a novel form of pressure-controlledtrip which is applied to the valve stem of each tire and includes means whereby the tire can be easily and conveniently inflated, there being associated with each trip and mounted -on the vehicle body a switch, so that when the trip is releasedbyv drop in tire pressure the trip will operate its associated switch and energize-the an nun'ciator and bell.

. With such objects view, and others which will appear as the description pro-.

ceeds, the invention comprises various novel features of construction and arrangement of parts such as will be set forth with .'.particularity in the following description and claims appended hereto.

In the accompanying drawings, which illustrate one embodiment of the invention,

and wherein similar characters of reference ularly to Fig. 3, 1, 2, 3' and 4 designate the four. wheels'of a. vehicle, which wheels. are each shod with a, pneumatic tire 5 that are supplied with air through an inflating stem 6, and applied to each stem is a combined inflating device and pressure controlled trip designated generally by A, the details of which are shown in Fig. 1. This device A consists of a tubular casing 7 which has fixed within it at a point somewhat below the upper end'a plug 8 which carries a tube.

9, there being on the upper end of the tube an internally-threaded socket 10 which screws onto a threaded nipple 11 on the extremity of the tire stem The casing 7 is externally threaded atits upper end and receives a jam nut 12 that is formed with an internal flange 13 which engages a shoulder formed by a flange 14 carried by the stem 6. By unscrewing the nut 12 the device A can be detached from the stem 6 by turning the device as a whole to unscrew the sockets 10 therein from the nipple 11, and of course the attachment of the device to the tire stem is effected in a reverse manis means for connection with an air pump or other inflating -means. This attaching means includes a tubular body 15 which screws into the casing 7 and plug 8 to com- Specification of Letters Patent. Patented J une 29, 1915,

Application filed Kay 5, 1914. Serial No. 836,429.

Extending laterallyfrom the casing the lower end of the casing 7 andholds the ring 9 tightly against the diaphragm.

The part of the diaphragm lying over the opening in the ring is capable of yielding downwardly and it operates on the head or' plunger 21 of a trigger pin 22, suchpin being movable in a guide formed by a disk 23 which is screwed in the casing 7. The trigger 22 is adapted normally to hold in retracted position a longitudinally movable trip 24'which extends transversely to and is slidable inthe lower end-of the cylinder 7. The trip has a plunger 25 carried certain point. A spring 29 is provided on the trigger 22 between the head or piston 21 thereof and the guide 23, and the tension of this spring is such that the trigger is adapted to be raised out of engagement with the trip 24 when the diaphragm 27 moves up: wardly by the diminution of. pressure in thentire. By adjusting the guide or disk 23 the tension may be varied. The outer end .of thetrip carries an adjustable striking element 30,.which, when the trip is released, assumes a position where, as the wheel rotates, it will operate a circuit closer and thereby. close an indicator andalarm circuit so that the driver will ,be informed that a tire. has lost its pressure and needs attention. 7

Associated with each wheel and mounted on the vehicle body, which latter is desigcloser C. This circuit closer in the present instance is'shown as a pivoted contact 31 which has an extension or arm 32 that is disposed in the path of the trip 24 so as to be struck by the element30 thereof when the trip is released and projected. Coiiperating with the contact 31, which is pivoted on a bracket 'or other support 33, is a pair of 5 spring contact fingers or members 34 which bracket 33 by insulation 35. Normally the contact 30 is out of engagement with either contact, element 34, and when the arm 32 is struck by the trip the circuit is closed by the contact 31 engaging either one of the contacts 34. The'contacts 34 are electrically connected with a binding'p'ost 36 which has connected therewith a circuit wire 37 The circuit wires 37- from the switches C, as- 6 sociated with the wheels 1, 2, 3 and 4. are

pressure in the tire is maintained above a.

nated by B, Fig. 1, is a switch or circuit are fastened to but insulated from the a held set by the trigger.

connected respectively with annunciators 4% 3, 2*" and 1, such annunciators being arranged in any suitable manner and preferably disposed in convenient view of the driver, as for instance on the dash 38 of the vehicle. The contact 31 is grounded on the bracket 33, which in turn isgrormded on the vehicle frame, and a wire 39 connects such vehicle frame with one terminal of a source of. current 40, the other terminal being connected by a wire 41, bell 42 and'wire 43 with the common wire44 ofthe annunciator. The cut-out switch 45 may be included in the circuit so as to enable the circuit to be thrown open when the vehicle is in a garage, so as .to prevent, in case of pressure falling in any tire, the circuit frombeing closed and wasting current. -Whenin operation any tire loses its pressure the trigger device thereof is released so that the switch associated with such tire will be closed and the annunciator for such tire will be energized so that the driver will know I Y which tire needs attention, the .signal or alarm 42 serving first to attract attention to p the condition ofthe tires. The circuit closer or switch C is of such design that it remains in closed position after having been once actuated, and therefore the driver must reset the switch manually.

From the foregoingdescription taken in.

connection with the accompanying draw ings, the advantages of the construction and method of operation will be readily under-- stood'by those skilled in the art to which the v invention appertains, and while I have de- I scribed the principle of operation. together with the 'device which I now consider to be the best embodiment thereof, I desire to have it understood that the device shown is merely illustrative, and that such changes may be made when desired as are within the scope of the appended claims.

Having thus described my invention, I claim as new and desire to secure by Letters Patent:

1. The combination of wheel, a the thereon, an inflating stem for the tire, a

combined inflating device and pressure re. sponsive means attached to the stem, a trip carried by the said means and controlled by the pressure responsive device, means for moving the trip when the said device loses control of the trip by the fall of pressure in the tire, a switch adapted to be. closed by said trip when the'same is released, and an .alarrn circuit controlled by the switch.

2. The combination of the inflating of a tire and a device connected therewith, said device including avalye-controlled inletthrough' which the tire is inflated, a diaphragm in the device and responsive to the r pressure in the tire, atrigger controlled the diaphragm. and a spring-pressed mp 3. The combination of a tire inflating stem, a casing, means for fastening the casing to the stem, a tube in the casin and communicating with the stem, an ating means communicating with the tube, a pressure responsive device in the casing and subjecte to the pressure in the tube, a trip carried by the casing and tending to move to signaling position, and means controlled by the pressure responsive device for releasa 1y holding the trip in non-signaling position. a v I 4. The combination of a tire inflating stem, a casing, means for fastening the casing to the stem, a tubein the casing and communicating with the stem, an inflating means communicating with the tube, a diaphragm in the casing and responsive to the pressure in the tube, a spring-pressed trigger operatively related to the diaphragm, and aqtrip normally engaged by the trigger and adapted to operate w enthe trigger releases by the fall in pressure on the diaphrag n.

5. he combination of a tire inflating stem, a casing, means for fastening the cas ing to the stem, a tube in the casin and communicating with'the stem, an i atin means communicating with the tube, a diaphragm in the casing and responsive to the pressure in the tube, a spring-pressed trigger operatively related to the diaphragm, a trip mounted in one end of the casing and extending transversely thereto and with which the trigger normally engages, and a spring actin on the trip for moving the same when e trigger is released.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

FRED PRENTISSFREEMAN.

Witnesses:

A. G. Farmer, W. F. Moms. 

